import Tabs from ‘@theme/Tabs’; import TabItem from ‘@theme/TabItem’;
Apache Druid Extension to enable using Kubernetes for launching and managing tasks instead of the Middle Managers. This extension allows you to launch tasks as kubernetes jobs removing the need for your middle manager.
Consider this an EXPERIMENTAL feature mostly because it has not been tested yet on a wide variety of long-running Druid clusters.
The K8s extension builds a pod spec for each task using the specified pod adapter. All jobs are natively restorable, they are decoupled from the Druid deployment, thus restarting pods or doing upgrades has no effect on tasks in flight. They will continue to run and when the overlord comes back up it will start tracking them again.
To use this extension please make sure to include druid-kubernetes-overlord-extensions in the extensions load list for your overlord process.
The extension uses druid.indexer.runner.capacity to limit the number of k8s jobs in flight. A good initial value for this would be the sum of the total task slots of all the middle managers you were running before switching to K8s based ingestion. The K8s task runner uses one thread per Job that is created, so setting this number too large can cause memory issues on the overlord. Additionally set the variable druid.indexer.runner.namespace to the namespace in which you are running druid.
Other configurations required are: druid.indexer.runner.type: k8s and druid.indexer.task.encapsulatedTask: true
Druid operators can dynamically tune certain features within this extension. You don't need to restart the Overlord service for these changes to take effect.
Druid can dynamically tune pod template selection, which allows you to configure the pod template based on the task to be run. To enable dynamic pod template selection, first configure the custom template pod adapter.
Use the following APIs to view and update the dynamic configuration for the Kubernetes task runner.
To use these APIs, ensure you have read and write permissions for the CONFIG resource type with the resource name “CONFIG”. For more information on permissions, see User authentication and authorization.
Retrieves the current dynamic execution config for the Kubernetes task runner. Returns a JSON object with the dynamic configuration properties.
GET /druid/indexer/v1/k8s/taskrunner/executionconfig
Successfully retrieved dynamic configuration
curl "http://ROUTER_IP:ROUTER_PORT/druid/indexer/v1/k8s/taskrunner/executionconfig"
GET /druid/indexer/v1/k8s/taskrunner/executionconfig HTTP/1.1 Host: http://ROUTER_IP:ROUTER_PORT
{ "type": "default", "podTemplateSelectStrategy": { "type": "selectorBased", "selectors": [ { "selectionKey": "podSpec1", "context.tags": { "userProvidedTag": ["tag1", "tag2"] }, "dataSource": ["wikipedia"] }, { "selectionKey": "podSpec2", "type": ["index_kafka"] } ] } }
Updates the dynamic configuration for the Kubernetes Task Runner
POST /druid/indexer/v1/k8s/taskrunner/executionconfig
The endpoint supports the following optional header parameters to populate the author and comment fields in the configuration history.
X-Druid-AuthorX-Druid-CommentSuccessfully updated dynamic configuration
curl "http://ROUTER_IP:ROUTER_PORT/druid/indexer/v1/k8s/taskrunner/executionconfig" \ --header 'Content-Type: application/json' \ --data '{ "type": "default", "podTemplateSelectStrategy": { "type": "selectorBased", "selectors": [ { "selectionKey": "podSpec1", "context.tags": { "userProvidedTag": ["tag1", "tag2"] }, "dataSource": ["wikipedia"] }, { "selectionKey": "podSpec2", "type": ["index_kafka"] } ] } }'
POST /druid/indexer/v1/k8s/taskrunner/executionconfig HTTP/1.1 Host: http://ROUTER_IP:ROUTER_PORT Content-Type: application/json { "type": "default", "podTemplateSelectStrategy": { "type": "selectorBased", "selectors": [ { "selectionKey": "podSpec1", "context.tags": { "userProvidedTag": ["tag1", "tag2"] }, "dataSource": ["wikipedia"] }, { "selectionKey": "podSpec2", "type": ["index_kafka"] } ] } }
A successful request returns an HTTP 200 OK message code and an empty response body.
Retrieves the history of changes to Kubernetes task runner's dynamic execution config over an interval of time. Returns an empty array if there are no history records available.
GET /druid/indexer/v1/k8s/taskrunner/executionconfig/history
The endpoint supports the following optional query parameters to filter results.
interval
/. For example, 2023-07-13/2023-07-19. The default interval is one week. You can change this period by setting druid.audit.manager.auditHistoryMillis in the runtime.properties file for the Coordinator.count
n entries.Successfully retrieved dynamic configuration
curl "http://ROUTER_IP:ROUTER_PORT/druid/indexer/v1/k8s/taskrunner/executionconfig/history"
GET /druid/indexer/v1/k8s/taskrunner/executionconfig/history HTTP/1.1 Host: http://ROUTER_IP:ROUTER_PORT
[ { "key": "k8s.taskrunner.config", "type": "k8s.taskrunner.config", "auditInfo": { "author": "", "comment": "", "ip": "127.0.0.1" }, "payload": "{\"type\": \"default\",\"podTemplateSelectStrategy\":{\"type\": \"taskType\"}", "auditTime": "2024-06-13T20:59:51.622Z" } ]
The logic defining how the pod template is built for your Kubernetes Job depends on which pod adapter you have specified.
The overlord single container pod adapter takes the podSpec of your Overlord pod and creates a kubernetes job from this podSpec. This is the default pod adapter implementation, to explicitly enable it you can specify the runtime property druid.indexer.runner.k8s.adapter.type: overlordSingleContainer
The overlord multi container pod adapter takes the podSpec of your Overlord pod and creates a kubernetes job from this podSpec. It uses kubexit to manage dependency ordering between the main container that runs your druid peon and other sidecars defined in the Overlord pod spec. Thus if you have sidecars such as Splunk or Istio it will be able to handle them. To enable this pod adapter you can specify the runtime property druid.indexer.runner.k8s.adapter.type: overlordMultiContainer
For the sidecar support to work for the multi container pod adapter, your entry point / command in docker must be explicitly defined your spec.
You can't have something like this: Dockerfile: ENTRYPOINT: ["foo.sh"]
and in your sidecar specs:
name: foo args: - arg1 - arg2
That will not work, because we cannot decipher what your command is, the extension needs to know it explicitly. *Even for sidecars like Istio which are dynamically created by the service mesh, this needs to happen.
Instead, do the following: You can keep your Dockerfile the same but you must have a sidecar spec like so:
name: foo command: foo.sh args: - arg1 - arg2
For both of these adapters, you can add optional labels to your K8s jobs / pods if you need them by using the following configuration: druid.indexer.runner.labels: '{"key":"value"}' Annotations are the same with: druid.indexer.runner.annotations: '{"key":"value"}'
All other configurations you had for the middle manager tasks must be moved under the overlord with one caveat, you must specify javaOpts as an array: druid.indexer.runner.javaOptsArray, druid.indexer.runner.javaOpts is no longer supported.
If you are running without a middle manager you need to also use druid.processing.intermediaryData.storage.type=deepstore
The custom template pod adapter allows you to specify a pod template file per task type for more flexibility on how to define your pods. This adapter expects a Pod Template to be available on the overlord's file system. This pod template is used as the base of the pod spec for the Kubernetes Job. You can override things like labels, environment variables, resources, annotation, or even the base image with this template. To enable this pod adapter you can specify the runtime property druid.indexer.runner.k8s.adapter.type: customTemplateAdapter
The base pod template must be specified as the runtime property druid.indexer.runner.k8s.podTemplate.base: /path/to/basePodSpec.yaml
The below runtime properties need to be passed to the Job's peon process.
druid.port=8100 (what port the peon should run on) druid.peon.mode=remote druid.service=druid/peon (for metrics reporting) druid.indexer.runner.type=k8s druid.indexer.task.encapsulatedTask=true
Note: Prior to Druid 35.0.0, you will need the druid.indexer.task.baseTaskDir runtime property, along with the TASK_DIR and attemptId arguments to /peon.sh to run your jobs. There is no need for that now as Druid will automatically configure the task directory. You can still choose to customize the target task directory by adjusting druid.indexer.task.baseTaskDir on the Overlord service.
apiVersion: "v1" kind: "PodTemplate" template: metadata: annotations: sidecar.istio.io/proxyCPU: "512m" # to handle an injected istio sidecar labels: app.kubernetes.io/name: "druid-realtime-backend" spec: affinity: {} containers: - command: - sh - -c - | /peon.sh env: - name: CUSTOM_ENV_VARIABLE value: "hello" image: apache/druid:{{DRUIDVERSION}} name: main ports: - containerPort: 8091 name: druid-tls-port protocol: TCP - containerPort: 8100 name: druid-port protocol: TCP resources: limits: cpu: "1" memory: 2400M requests: cpu: "1" memory: 2400M volumeMounts: - mountPath: /opt/druid/conf/druid/cluster/master/coordinator-overlord # runtime props are still mounted in this location because that's where peon.sh looks for configs name: nodetype-config-volume readOnly: true - mountPath: /druid/data name: data-volume - mountPath: /druid/deepstorage name: deepstorage-volume restartPolicy: "Never" securityContext: fsGroup: 1000 runAsGroup: 1000 runAsUser: 1000 tolerations: - effect: NoExecute key: node.kubernetes.io/not-ready operator: Exists tolerationSeconds: 300 - effect: NoExecute key: node.kubernetes.io/unreachable operator: Exists tolerationSeconds: 300 volumes: - configMap: defaultMode: 420 name: druid-tiny-cluster-peons-config name: nodetype-config-volume - emptyDir: {} name: data-volume - emptyDir: {} name: deepstorage-volume
Any runtime property or JVM config used by the peon process can also be passed. E.G. below is an example of a ConfigMap that can be used to generate the nodetype-config-volume mount in the above template.
apiVersion: v1 kind: ConfigMap metadata: name: druid-tiny-cluster-peons-config namespace: default data: jvm.config: |- -server -XX:MaxDirectMemorySize=1000M -Duser.timezone=UTC -Dfile.encoding=UTF-8 -Dlog4j.debug -Djava.util.logging.manager=org.apache.logging.log4j.jul.LogManager -Djava.io.tmpdir=/druid/data -Xmx1024M -Xms1024M log4j2.xml: |- <?xml version="1.0" encoding="UTF-8" ?> <Configuration status="WARN"> <Appenders> <Console name="Console" target="SYSTEM_OUT"> <PatternLayout pattern="%d{ISO8601} %p [%t] %c - %m%n"/> </Console> </Appenders> <Loggers> <Root level="info"> <AppenderRef ref="Console"/> </Root> </Loggers> </Configuration> runtime.properties: | druid.port=8100 druid.service=druid/peon druid.server.http.numThreads=5 druid.indexer.runner.type=k8s druid.peon.mode=remote druid.indexer.task.encapsulatedTask=true
Alternatively, we can mount the ConfigMap onto Overlord services, and use the ConfigMap to generate the pod template files we want.
volumeMounts: - name: druid-pod-templates mountPath: /path/to/podTemplate/directory volumes: - name: druid-pod-templates configMap: name: druid-pod-templates
apiVersion: v1 kind: ConfigMap metadata: name: druid-pod-templates data: basePodSpec.yaml: |- apiVersion: "v1" kind: "PodTemplate" template: metadata: labels: app.kubernetes.io/name: "druid-realtime-backend" annotations: sidecar.istio.io/proxyCPU: "512m" spec: containers: - name: main image: apache/druid:{{DRUIDVERSION}} command: - sh - -c - | /peon.sh env: - name: druid_port value: 8100 - name: druid_plaintextPort value: 8100 - name: druid_tlsPort value: 8091 - name: druid_peon_mode value: remote - name: druid_service value: "druid/peon" - name: druid_indexer_runner_type value: k8s - name: druid_indexer_task_encapsulatedTask value: true ports: - containerPort: 8091 name: druid-tls-port protocol: TCP - containerPort: 8100 name: druid-port protocol: TCP resources: limits: cpu: "1" memory: 2400M requests: cpu: "1" memory: 2400M restartPolicy: "Never" securityContext: fsGroup: 1000 runAsGroup: 1000 runAsUser: 1000 tolerations: - effect: NoExecute key: node.kubernetes.io/not-ready operator: Exists tolerationSeconds: 300 - effect: NoExecute key: node.kubernetes.io/unreachable operator: Exists tolerationSeconds: 300
Whenever the Overlord wants to spin up a Kubernetes task pod, it will first read the relevant pod template file, and then create a task pod according to the specifications of the pod template file. This is helpful when you want to make configuration changes to the task pods (e.g. increase/decrease CPU limit or resources). You can edit the pod template files directly, and the next task pod spun up by the Overlord will reflect these changes in its configurations.
The pod template adapter can select which pod template should be used for a task using the task runner execution config
The TaskTypePodTemplateSelectStrategy strategy selects pod templates based on task type for execution purposes, implementing the behavior that maps templates to specific task types. This is the default pod template selection strategy. To explicitly select this strategy, set the podTemplateSelectStrategy in the dynamic execution config to
{ "type": "default" }
Task specific pod templates can be specified as the runtime property druid.indexer.runner.k8s.podTemplate.{taskType}: /path/to/taskSpecificPodSpec.yaml where {taskType} is the name of the task type. For example, index_parallel.
If you are trying to use the default image's environment variable parsing feature to set runtime properties, you need to add an extra escape underscore when specifying pod templates. For example, set the environment variable druid_indexer_runner_k8s_podTemplate_index__kafka when you set the runtime property druid.indexer.runner.k8s.podTemplate.index_kafka
The following example shows a configuration for task-based pod template selection:
druid.indexer.runner.k8s.podTemplate.base=/path/to/basePodSpec.yaml druid.indexer.runner.k8s.podTemplate.index_kafka=/path/to/kafkaPodSpec.yaml
The SelectorBasedPodTemplateSelectStrategy strategy evaluates a series of criteria within selectors to determine which pod template to use to run the task. Pod templates are configured in the runtime properties like druid.indexer.runner.k8s.podTemplate.<selectionKey>=....
{ "type": "selectorBased", "selectors": [ { "selectionKey": "podSpec1", "context.tags": { "userProvidedTag": ["tag1", "tag2"] }, "dataSource": ["wikipedia"] }, { "selectionKey": "podSpec2", "type": ["index_kafka"] } ] }
Selectors are processed in order. Druid selects the template based on the first matching selector. If a task does not match any selector in the list, it will use the base pod template.
For a task to match a selector, all the conditions within the selector must match. A selector can match on
type: Type of the taskdataSource: Destination datasource of the task.context.tags: Tags passed in the task's context.Set the following runtime properties to define the pod specs that can be used by Druid.
druid.indexer.runner.k8s.podTemplate.base=/path/to/basePodSpec.yaml druid.indexer.runner.k8s.podTemplate.podSpec1=/path/to/podSpecWithHighMemRequests.yaml druid.indexer.runner.k8s.podTemplate.podSpec2=/path/to/podSpecWithLowCpuRequests.yaml
Set the dynamic execution config to define the pod template selection strategy.
{ "type": "default", "podTemplateSelectStrategy": { "type": "selectorBased", "selectors": [ { "selectionKey": "podSpec1", "context.tags": { "userProvidedTag": ["tag1", "tag2"] }, "dataSource": ["wikipedia"] }, { "selectionKey": "podSpec2", "type": ["index_kafka"] } ] } }
Druid selects the pod templates as follows:
podSpecWithHighMemRequests.yaml when both of the following conditions are met:userProvidedTag that has the value tag1 or tag2.wikipedia datasource.podSpecWithLowCpuRequests.yaml when the task type is index_kafka.basePodSpec.yaml for all other tasks.In this example, if there is an index_kafka task for the wikipedia datasource with the tag userProvidedTag: tag1, Druid selects the pod template podSpecWithHighMemRequests.yaml.
In the above example, for selection key podSpec1 we didn't specify task type. This is equivalent to setting type to null or an empty array. All three examples below are equivalent.
Not setting type
{ "selectionKey": "podSpec1", "context.tags": { "userProvidedTag": ["tag1", "tag2"] }, "dataSource": ["wikipedia"] }
Setting type to null
{ "selectionKey": "podSpec1", "context.tags": { "userProvidedTag": ["tag1", "tag2"] }, "dataSource": ["wikipedia"], "type": null }
Setting type to an empty array
{ "selectionKey": "podSpec1", "context.tags": { "userProvidedTag": ["tag1", "tag2"] }, "dataSource": ["wikipedia"], "type": [] }
In all the above cases, Druid will match the selector to any value of task type. Druid applies similar logic for dataSource. For context.tags setting null or an empty object {} is equivalent.
It is possible to run task pods in a different namespace from the rest of your Druid cluster.
If you are running multiple Druid clusters and would like to have a dedicated namespace for all your task pods, you can make the following changes to the runtime properties for your Overlord deployment:
druid.indexer.runner.namespace: The namespace where the task pods will run. It can be the same as the namespace where your Druid cluster is deployed, or different from it. In the latter case, you need to define the following overlordNamespace.druid.indexer.runner.overlordNamespace: The namespace where the Overlord resides. This must be defined when tasks are scheduled in different namespace.druid.indexer.runner.k8sTaskPodNamePrefix (Optional): Self-defined field to differentiate which task pods are created from which namespace. More information here.Warning: When druid.indexer.runner.overlordNamespace and druid.indexer.runner.k8sTaskPodNamePrefix is configured, users should ensure that all running tasks are stopped when changing these values. Failure to do so will cause the Overlord to lose track of running tasks, and re-launch them. This may lead to duplicate data and possibly metadata inconsistency issues.
Druid will tag Kubernetes jobs with a druid.overlord.namespace label. This label helps Druid filter out Kubernetes jobs belonging to other namespaces. Should you need to deploy a Druid cluster on a namespace N1 that is already running tasks from another namespace N2, take note to set druid.indexer.runner.overlordNamespace to druid.indexer.runner.namespace (which is N1). Failure to do so will result in the cluster in N1 detecting task pods created from both N1 and N2.
When we have task pods started by Overlord servers of different Druid clusters, running in different K8S namespaces, it will be difficult to tell which task pods are being started by which overlord or Druid cluster. You can specify a task name prefix, druid.indexer.runner.k8sTaskPodNamePrefix, to apply your specified prefix to all task pods created by your cluster.
After configuration, you can witness the change from coordinatorissuedcompactdataso-0e74d5132781cc950eecf04--1-vbx6t to yourtaskprefix-0e74d5132781cc950eecf04--1-vbx6t by either doing kubectl get pods or by viewing the “Location” column under the web console.
When configuring the druid.indexer.runner.k8sTaskPodNamePrefix, you should note that:
: - . _ will be ignored.Ensure that when you are running task pods in another namespace, your task pods are able to communicate with ZooKeeper which might be deployed in the same namespace with overlord. If you are using custom pod templates as described below, you can configure druid.zk.service.host to your tasks.
Should you require the needed permissions for interacting across Kubernetes namespaces, you can specify a kubeconfig file, and provided the necessary permissions. You can then use the KUBECONFIG environment variable to allow your Overlord deployment to find your kubeconfig file. Refer to the Kubernetes documentation for more information.
| Property | Possible Values | Description | Default | Required |
|---|---|---|---|---|
druid.indexer.runner.namespace | String | If Overlord and task pods are running in different namespaces, specify the Overlord namespace. | - | Yes |
druid.indexer.runner.overlordNamespace | String | Only applicable when using Custom Template Pod Adapter. If Overlord and task pods are running in different namespaces, specify the Overlord namespace. Warning: You need to stop all running tasks in Druid to change this property. Failure to do so will lead to duplicate data and metadata inconsistencies. | "" | No |
druid.indexer.runner.k8sTaskPodNamePrefix | String | Use this if you want to change your task name to contain a more human-readable prefix. Maximum 30 characters. Special characters : - . _ will be ignored. Warning: You need to stop all running tasks in Druid to change this property. Failure to do so will lead to duplicate data and metadata inconsistencies. | "" | No |
druid.indexer.runner.debugJobs | boolean | Boolean flag used to disable clean up of K8s jobs after tasks complete. | False | No |
druid.indexer.runner.sidecarSupport | boolean | Deprecated, specify adapter type as runtime property druid.indexer.runner.k8s.adapter.type: overlordMultiContainer instead. If your overlord pod has sidecars, this will attempt to start the task with the same sidecars as the overlord pod. | False | No |
druid.indexer.runner.primaryContainerName | String | If running with sidecars, the primaryContainerName should be that of your druid container like druid-overlord. | First container in podSpec list | No |
druid.indexer.runner.kubexitImage | String | Used kubexit project to help shutdown sidecars when the main pod completes. Otherwise, jobs with sidecars never terminate. | karlkfi/kubexit:latest | No |
druid.indexer.runner.disableClientProxy | boolean | Use this if you have a global http(s) proxy and you wish to bypass it. | false | No |
druid.indexer.runner.maxTaskDuration | Duration | Max time a task is allowed to run for before getting killed. | PT4H | No |
druid.indexer.runner.taskCleanupDelay | Duration | How long do jobs stay around before getting reaped from K8s. | P2D | No |
druid.indexer.runner.taskCleanupInterval | Duration | How often to check for jobs to be reaped. | PT10M | No |
druid.indexer.runner.taskJoinTimeout | Duration | Timeout for gathering metadata about existing tasks on startup. | PT1M | No |
druid.indexer.runner.k8sjobLaunchTimeout | Duration | How long to wait to launch a K8s task before marking it as failed, on a resource constrained cluster it may take some time. | PT1H | No |
druid.indexer.runner.javaOptsArray | JsonArray | java opts for the task. | -Xmx1g | No |
druid.indexer.runner.labels | JsonObject | Additional labels you want to add to peon pod. | {} | No |
druid.indexer.runner.annotations | JsonObject | Additional annotations you want to add to peon pod. | {} | No |
druid.indexer.runner.peonMonitors | JsonArray | Overrides druid.monitoring.monitors. Use this property if you don't want to inherit monitors from the Overlord. | [] | No |
druid.indexer.runner.graceTerminationPeriodSeconds | Long | Number of seconds you want to wait after a sigterm for container lifecycle hooks to complete. Keep at a smaller value if you want tasks to hold locks for shorter periods. | PT30S (K8s default) | No |
druid.indexer.runner.capacity | Integer | Number of concurrent jobs that can be sent to Kubernetes. | 2147483647 | No |
druid.indexer.runner.cpuCoreInMicro | Integer | Number of CPU micro core for the task. | 1000 | No |
druid.indexer.runner.logSaveTimeout | Duration | How long to wait for task logs to be saved before giving up. | PT300S | NO |
| Metric | Description | Dimensions | Normal value |
|---|---|---|---|
k8s/peon/startup/time | Metric indicating the milliseconds for peon pod to startup. | dataSource, taskId, taskType, groupId, taskStatus, tags | Varies |
With the exception of task pods, all Druid Pods belonging to one Druid cluster must be inside the same Kubernetes namespace.
You must have a role binding for the overlord's service account that provides the needed permissions for interacting with Kubernetes. An example spec could be:
kind: Role apiVersion: rbac.authorization.k8s.io/v1 metadata: namespace: <druid-namespace> name: druid-k8s-task-scheduler rules: - apiGroups: ["batch"] resources: ["jobs"] verbs: ["get", "watch", "list", "delete", "create"] - apiGroups: [""] resources: ["events", "pods", "pods/log"] verbs: ["get", "watch", "list", "delete", "create"] --- kind: RoleBinding apiVersion: rbac.authorization.k8s.io/v1 metadata: name: druid-k8s-binding namespace: <druid-namespace> subjects: - kind: ServiceAccount name: <druid-overlord-k8s-service-account> namespace: <druid-namespace> roleRef: kind: Role name: druid-k8s-task-scheduler apiGroup: rbac.authorization.k8s.io
:::info This feature is only available starting in Druid 28. If you require a rolling update to enable Kubernetes-based ingestion, first update your cluster to Druid 28 then apply the overlord configurations mentioned in this section. :::
If you are running a cluster with tasks running on middle managers or indexers and want to do a zero downtime migration to mm-less ingestion, the mm-less ingestion system is capable of running in migration mode by reading tasks from middle managers/indexers and Kubernetes and writing tasks to either middle managers or to Kubernetes.
To do this, set the following property. druid.indexer.runner.type: k8sAndWorker (instead of druid.indexer.runner.type: k8s)
| Property | Possible Values | Description | Default | required |
|---|---|---|---|---|
druid.indexer.runner.k8sAndWorker.runnerStrategy.type | String (e.g., k8s, worker, taskType) | Defines the strategy for task runner selection. | k8s | No |
druid.indexer.runner.k8sAndWorker.runnerStrategy.workerType | String (e.g., httpRemote, remote) | Specifies the variant of the worker task runner to be utilized. | httpRemote | No |
For taskType runner strategy: | ||||
druid.indexer.runner.k8sAndWorker.runnerStrategy.taskType.default | String (e.g., k8s, worker) | Specifies the default runner to use if no overrides apply. This setting ensures there is always a fallback runner available. | None | No |
druid.indexer.runner.k8sAndWorker.runnerStrategy.taskType.overrides | JsonObject(e.g., {"index_kafka": "worker"}) | Defines task-specific overrides for runner types. Each entry sets a task type to a specific runner, allowing fine control. | {} | No |